This invention relates to an input device, and more particularly it relates to a membrane-type of input device for introducing electrical signals into a microcomputer-based circuit or other circuits.
To accomplish a wide range of functions in a variety of household appliances including microwave ovens, microcomputers are in increasing use. A number of key switches, variable resistors of rotary or slide type and the like are used in conjunction with those microcomputers for introduction of electrical signals thereto. In the case of microwave ovens, variable resistors are more advantageous than key switches for entering numerical representations of heating parameters such as time and temperature because the former demands merely selecting a desired resistance value while the latter requires actuation of a desired number of key switches. Even though it is advantageous in the above aspect, the variable resistor has inherent disadvantages in that the structure is complex and costly and its protruding knob is difficult to clean. The last problem is critical especially in microwave ovens which should be constantly kept clean.